Re: [PATCH v2 2/3] commit: refuse to amend during conflict resolution
- From
- Phillip Wood <phillip.wood123@gmail.com>
- Date
- Aug 27, 2026, 15:19 UTC
- Message-ID
- <aa248030-5275-465b-a4b5-683ca374672c@gmail.com>
- In-Reply-To
- <4a1461e52767227d9475de13cf250484f8ecd271.1787792534.git.gitgitgadget@gmail.com>
Hi Elijah
On 27/08/2026 02:02, Elijah Newren via GitGitGadget wrote:
Show 30 quoted lines
> From: Elijah Newren <newren@gmail.com>
>
> diff --git a/builtin/commit.c b/builtin/commit.c
> index 0d908d72bb..4a6054aae0 100644
> --- a/builtin/commit.c
> +++ b/builtin/commit.c
> @@ -1326,15 +1326,30 @@ static int parse_and_validate_options(int argc, const char *argv[],
> use_editor = 0;
>
> /* Sanity check options */
> - if (amend && !current_head)
> - die(_("You have nothing to amend."));
> - if (amend && whence != FROM_COMMIT) {
> - if (whence == FROM_MERGE)
> + if (amend) {
> + if (!current_head)
> + die(_("You have nothing to amend."));
> + /*
> + * Refuse to amend in the middle of any operation that is
> + * meant to record its result as a new commit on top of HEAD
> + * rather than by rewriting HEAD.
> + */
> + switch (sequencer_ongoing_operation(s->repo, whence)) {
> + case ONGOING_NONE:
> + break;
> + case ONGOING_MERGE:
> die(_("You are in the middle of a merge -- cannot amend."));
> - else if (is_from_cherry_pick(whence))
> + case ONGOING_CHERRY_PICK:
> die(_("You are in the middle of a cherry-pick -- cannot amend."));For rebase we distinguish between a conflict and a commit that becomes empty, but we don't do that for a cherry-pick. That's an existing problem though, not something we necessarily need to address in this series.
Moving the detection to a separate function and using an enum here is much nicer than the previous version.
Show 29 quoted lines
> diff --git a/sequencer.c b/sequencer.c
> index 65afd100d9..bd4a724410 100644
> --- a/sequencer.c
> +++ b/sequencer.c
> @@ -6966,6 +6966,71 @@ int sequencer_determine_whence(struct repository *r, enum commit_whence *whence)
> return 0;
> }
>
> +enum ongoing_operation sequencer_ongoing_operation(struct repository *r,
> + enum commit_whence whence)
> +{
> [...]
> + /*
> + * In the middle of a rebase that stopped for conflict resolution?
> + * The apply backend only ever stops for conflicts, so the presence
> + * of its state directory is enough. The merge backend writes
> + * stopped-sha whenever it hands control back to the user, but omits
> + * `amend` unless it stopped with HEAD already pointing at the commit
> + * to be amended (a clean edit/reword stop); its absence therefore
> + * marks a conflicted stop.
> + */
> + path = repo_git_path(r, "rebase-apply");
> + found = file_exists(path);
> + free(path);
> + if (!found) {
> + char *stopped_sha = repo_git_path(r, "rebase-merge/stopped-sha");
> + char *amend_marker = repo_git_path(r, "rebase-merge/amend");
> +
> + found = file_exists(stopped_sha) && !file_exists(amend_marker);The sequencer defines rebase_path_stoppend_sha() and rebase_path_amend() so we can avoid having to hard code these paths throughout the code. Apart from that this all looks good to me.
Thanks
Phillip
Show 188 quoted lines
> + free(stopped_sha);
> + free(amend_marker);
> + }
> + if (found)
> + return ONGOING_REBASE_CONFLICT;
> +
> + return ONGOING_NONE;
> +}
> +
> int sequencer_get_update_refs_state(const char *wt_dir,
> struct string_list *refs)
> {
> diff --git a/sequencer.h b/sequencer.h
> index 64a9c7fb1b..3a4bd97db1 100644
> --- a/sequencer.h
> +++ b/sequencer.h
> @@ -277,6 +277,29 @@ int sequencer_get_last_command(struct repository* r,
> enum replay_action *action);
> int sequencer_determine_whence(struct repository *r, enum commit_whence *whence);
>
> +/*
> + * An in-progress operation that records its result (often a conflict
> + * resolution) as a new commit on top of HEAD, during which amending
> + * HEAD via "git commit --amend" is almost always a mistake.
> + */
> +enum ongoing_operation {
> + ONGOING_NONE = 0,
> + ONGOING_MERGE,
> + ONGOING_CHERRY_PICK,
> + ONGOING_REBASE_EMPTY,
> + ONGOING_REVERT,
> + ONGOING_AM,
> + ONGOING_REBASE_CONFLICT
> +};
> +
> +/*
> + * Return which in-progress operation, if any, is underway; see enum
> + * ongoing_operation. 'whence' is the origin already computed for the
> + * pending commit.
> + */
> +enum ongoing_operation sequencer_ongoing_operation(struct repository *r,
> + enum commit_whence whence);
> +
> /**
> * Append the set of ref-OID pairs that are currently stored for the 'git
> * rebase --update-refs' feature if such a rebase is currently happening.
> diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
> index 1e78dbfd90..7cf06e5f9a 100755
> --- a/t/t3404-rebase-interactive.sh
> +++ b/t/t3404-rebase-interactive.sh
> @@ -1884,6 +1884,93 @@ test_expect_success 'correct error message for commit --amend after empty pick'
> test_grep "resolving a commit that became empty -- cannot amend." err
> '
>
> +test_expect_success 'commit --amend is refused at a rebase conflict stop' '
> + test_when_finished "git rebase --abort" &&
> + git checkout --detach conflict-branch &&
> + (
> + set_fake_editor &&
> + FAKE_LINES="1 3" &&
> + export FAKE_LINES &&
> + test_must_fail git rebase -i A
> + ) &&
> + test_path_is_file .git/rebase-merge/patch &&
> + test_path_is_missing .git/rebase-merge/amend &&
> + echo resolved >conflict &&
> + git add conflict &&
> + test_must_fail git commit --amend --no-edit 2>err &&
> + test_grep "You are resolving conflicts during a rebase -- cannot amend" err
> +'
> +
> +test_expect_success 'commit --amend is refused when an "edit" pick conflicts' '
> + test_when_finished "git rebase --abort" &&
> + git checkout --detach conflict-branch &&
> + (
> + set_fake_editor &&
> + FAKE_LINES="1 edit 3" &&
> + export FAKE_LINES &&
> + test_must_fail git rebase -i A
> + ) &&
> + test_path_is_file .git/rebase-merge/patch &&
> + test_path_is_missing .git/rebase-merge/amend &&
> + echo resolved >conflict &&
> + git add conflict &&
> + test_must_fail git commit --amend --no-edit 2>err &&
> + test_grep "You are resolving conflicts during a rebase -- cannot amend" err
> +'
> +
> +test_expect_success 'commit --amend is allowed at a rebase edit stop' '
> + test_when_finished "git rebase --abort" &&
> + git checkout --detach no-conflict-branch &&
> + (
> + set_fake_editor &&
> + FAKE_LINES="edit 1 2 3 4" &&
> + export FAKE_LINES &&
> + git rebase -i A
> + ) &&
> + test_path_is_file .git/rebase-merge/amend &&
> + echo tweak >fileJ &&
> + git add fileJ &&
> + git commit --amend --no-edit
> +'
> +
> +test_expect_success 'commit --amend is allowed at a rebase break stop' '
> + test_when_finished "git rebase --abort" &&
> + git checkout --detach no-conflict-branch &&
> + (
> + set_fake_editor &&
> + FAKE_LINES="break 1 2 3 4" &&
> + export FAKE_LINES &&
> + git rebase -i A
> + ) &&
> + test_must_fail git rev-parse --verify REBASE_HEAD &&
> + echo tweak >fileJ &&
> + git add fileJ &&
> + git commit --amend --no-edit
> +'
> +
> +test_expect_success 'commit --amend is refused at an apply-backend conflict stop' '
> + test_when_finished "rm -rf apply-backend" &&
> + test_create_repo apply-backend &&
> + (
> + cd apply-backend &&
> + test_commit base file &&
> + git branch -M mainline &&
> + test_commit upstream file upstream &&
> + git checkout -b side mainline~1 &&
> + test_commit conflicting file side &&
> + test_commit unrelated other &&
> + test_must_fail git rebase --apply mainline &&
> + # the apply backend only ever stops for conflicts, and
> + # leaves HEAD on the previously-applied commit
> + test_path_is_dir .git/rebase-apply &&
> + test_path_is_missing .git/rebase-apply/applying &&
> + echo resolved >file &&
> + git add file &&
> + test_must_fail git commit --amend --no-edit 2>err &&
> + test_grep "You are resolving conflicts during a rebase -- cannot amend" err
> + )
> +'
> +
> test_expect_success 'todo has correct onto hash' '
> GIT_SEQUENCE_EDITOR=cat git rebase -i no-conflict-branch~4 no-conflict-branch >actual &&
> onto=$(git rev-parse --short HEAD~4) &&
> diff --git a/t/t3507-cherry-pick-conflict.sh b/t/t3507-cherry-pick-conflict.sh
> index 44596cb1e8..42de398f76 100755
> --- a/t/t3507-cherry-pick-conflict.sh
> +++ b/t/t3507-cherry-pick-conflict.sh
> @@ -364,6 +364,17 @@ test_expect_success 'failed revert sets REVERT_HEAD' '
> test_cmp_rev picked REVERT_HEAD
> '
>
> +test_expect_success 'commit --amend of revert fails' '
> + pristine_detach initial &&
> +
> + test_must_fail git revert picked &&
> + echo resolved >foo &&
> + git add foo &&
> + test_must_fail git commit --amend 2>err &&
> +
> + test_grep "in the middle of a revert -- cannot amend." err
> +'
> +
> test_expect_success 'successful revert does not set REVERT_HEAD' '
> pristine_detach base &&
> git revert base &&
> diff --git a/t/t4151-am-abort.sh b/t/t4151-am-abort.sh
> index 8e1ecf8a68..9313a074b2 100755
> --- a/t/t4151-am-abort.sh
> +++ b/t/t4151-am-abort.sh
> @@ -63,6 +63,17 @@ do
>
> done
>
> +test_expect_success 'commit --amend during a failed am fails' '
> + git reset --hard initial &&
> + cp file-2-expect file-2 &&
> + test_must_fail git am 000[1245]-*.patch &&
> + echo resolved >file-1 &&
> + git add file-1 &&
> + test_must_fail git commit --amend 2>err &&
> + test_grep "in the middle of an am session -- cannot amend." err &&
> + git am --abort
> +'
> +
> test_expect_success 'am -3 --skip removes otherfile-4' '
> git reset --hard initial &&
> test_must_fail git am -3 0003-*.patch &&